Note 85 — PROGRESSION IN OR THROUGH THE AIR. (continued 2)
Reading edition
“The os humeri, or bone of the arm, is articulated by a small rounded surface to a corresponding cavity formed between the coracoid bone and the scapula, in such a manner as to allow great freedom of motion.”—Macgillivray’s Brit. Birds, vol. i. p. 33.
“The arm is articulated to the trunk by a ball-and-socket joint, permitting all the freedom of motion necessary for flight.”—Cyc. of Anat. and Phys., vol. iii. p. 424.